When installing braces or other orthodontic apparatus in a patient's mouth, orthodontists typically apply orthodontic bands to the patient's teeth. Orthodontic bands come in a variety of shapes a sizes to fit many variations of mandibular and maxillary molars and bicuspids. A typical orthodontic band 10 is shown in FIG. 1. Band 10 comprises a quasi-annular shaped piece of material with an inner surface 12, an outer surface 14 and upper and lower edges 16, 18. Typically, band 10 is typically formed from deformable and non-reactive materials, such as metals and metal alloys for example.
The application of an orthodontic band to a patient's tooth is commonly referred to as “seating” the band. Seating band 10 on a patient's tooth typically involves pushing band 10 over the tooth, such that inner surface 12 fits snugly against and circumferentially surrounds the outer surface of the tooth. Adhesive may be applied between inner surface 12 and the outer surface of the tooth to help secure band 10 to the tooth. Typically, the tooth does not perfectly match the outline of the chosen band 10 and, consequently, band 10 must be deformed as it is seated to conform its shape to that of the tooth. Seating an orthodontic band may require application of a considerable amount of force to deform the band and to push the band over the outer surface of the tooth.
Brackets or other orthodontic apparatus may be mounted or otherwise coupled to band 10. Orthodontic band 10 may incorporate various attachment features (not shown), which assist in coupling an orthodontic apparatus to the band. Bands 10 are often adapted to the shape of a tooth at a preliminary appointment, then sent on a model of the dental arch to an orthodontic lab for modification with various attachment features which may be welded or otherwise attached to band 10. The patient then returns to the orthodontist for final seating and cementation, where band 10 is affixed to the patient's tooth.
Because of the considerable amount of force required to seat orthodontic bands and because of the confined space within a patient's mouth, orthodontists usually use a tool to assist with seating orthodontic bands. Such tools are typically referred to as “band seaters” or “band seating tools.” Band seating tools typically have an elongated shaft or handle, which the orthodontist uses to grip and manipulate the tool; and a post, which projects from an opposite end of the tool. While gripping the tool by the shaft or handle, the orthodontist typically seats a band on a tooth by pushing or otherwise forcing the band onto the tooth using the post of the band seating tool. Some known band seating tools allow a patient to bite down on the tool, so that, rather than the orthodontist applying force to the band through the band seating tool, the force required to seat the band is transferred from the patient's jaw through the handle and post of the seating tool and onto the band.
Prior art band seating tools are disclosed in:    U.S. Pat. No. 2,835,972 (Sheldon);    U.S. Pat. No. 3,360,861 (Hoffman);    U.S. Pat. No. 1,261,339 (Angle);    U.S. Pat. No. 4,192,068 (Wolfson); and    U.S. Pat. No. 3,797,116 (Meeks Jr.).
One drawback with prior art band seating tools is that their posts are often prone to slipping off of the relatively thin edge of the band when they are used to seat the band (see edge 16 of band 10 in FIG. 1). If this occurs, the post and/or other parts of the band seating tool may damage the patient's teeth and/or gingiva. This is particularly problematic in view of the considerable forces used to seat ;orthodontic bands. Another problem with many prior art band seating tools is that they have only one post. When an orthodontist uses a single post band seating tool to apply force to one side of a band, the band may slide around the outer surface of the tooth, unseating the opposing side of the band.
The prior art band seating tool disclosed in U.S. Pat. No. 3,797,116 (Meeks, Jr.) has a pair of posts which are used to apply force to opposing sides of an orthodontic band. However, these are straight posts, which are disposed at a fixed angle (relative to the shaft of the tool), such that the posts diverge from one another as they extend away from the shaft. This diverging angular orientation imports (to forces transferred through the posts to the band) force components that are oriented away from the outer surface of the tooth. These force components tend to increase the likelihood for either or both posts to slip off of the edge of the band, potentially injuring the patient. Further, when applying an orthodontic band such as band 10 to a mandibular tooth, the diverging posts of the Meeks Jr. tool would tend to spread the upper band edges 16, distorting them away from the tooth surface, rather than providing the close fit desired between the inner band surface 12 and the outer tooth surface. As the posts of the Meeks Jr. tool are fixed (not adjustable), a large selection of similar tools are required to accommodate variations in size and/or angulation of patient teeth.
This invention addresses the foregoing problems.